NEW YORK, April 17 (Reuters) - From final fittings at a famous Parisian fashion house to rehearsals for a young choreographer's new work for the New York City Ballet and a global tour of "Richard III," documentaries at the Tribeca Film Festival give viewers the film equivalent of a backstage pass.

This year documentaries run the gamut of topics from digital currency in "The Rise and Rise of Bitcoin," to the last natural habitat for Africa's endangered mountain gorillas in "Virunga" and "Misconception" about the consequences of world population growth.

"Dior and I," which opens on Thursday, follows creative director Raf Simons, 46, as he prepares his first couture collection for Christian Dior, and uncovers similarities between the Belgian designer and the French founder of the famous Parisian fashion house.

"There were all these uncanny things," said New York-based, French-born director Frederic Tcheng about the two men, both shy, reserved and inspired by the arts.

"There was a sense of reincarnation," he added.

Using voiceover excerpts from Dior's 1956 memoir "Christian Dior & I," Tcheng introduces viewers to Dior, both the man and the fashion house he created.

He shows how Simons created his 2012 collection with its strapless, full-skirted gowns in printed art-inspired patterns, flowing dresses with belted waists and feminine but sexy pant outfits.

"The goal for me as a documentary filmmaker is always to expand your horizons and in the case of this film getting to know seamstresses and their work and having access to this social environment that I really didn't know," Tcheng said.

"This is the closest I've come to a subject," said the director who has also worked on films about Italian designer Valentino and fashion Diana Vreeland, who died in 1989.

BALLET AND SHAKESPEARE

Director Jody Lee Lipes takes a fly-on-the-way approach in "Ballet 422" as New York City Ballet dancer Justin Peck, 25, choreographed an original ballet for the company founded by George Balanchine in the 1940s.

From the first rehearsal with the dancers of the ballet called Paz de la Jolla, the 422nd new work for the company, through costume fittings, lighting changes and music adjustments, to the jitters of opening night Lipes follows Peck with seemingly unfettered access through every step of the process.

He even ventures with Peck into the audience as he watches their reaction on opening night.

Peck, now a soloist, joined the ballet company in 2007. Paz de la Jolla, which debuted in January 2013, is his third work for New York City Ballet.

Audiences also go behind the scenes in director Jeremy Whelehan's "Now: In the Wings on a World Stage," with double Academy Award-winner Kevin Spacey ("American Beauty" and "The Usual Suspects") and director Sam Mendes, who won a directing Oscar in 2000 for "American Beauty," as they take "Richard III" on the road across three continents.

The production was their first collaboration in more than a decade. The film follows the tour from London, to Doha, China, Turkey, Singapore, Australia, Italy, Hong Kong and the United States.

"There are a multitude of challenges that come with being in a new theater in an unknown city every few weeks. There were some tears, but also a lot of laughs," Spacey said about the film.